Of same place



(No Model.) x z Sheets-Sheet 1. W W. DEAN. TELEPHONE SYSTEM.

No. 593,372. Pidtented Nov; 9, 1897;;

. W. W. DEA N. TELEPHONE SYSTEM.-

2 Sheets-Sheet 2.

(No Model.)

Patented NOV. 9, 1897.

zyzzzzwlwjwg UNITED STATES W'I-LLIAM W. DEAN, OF ST. LOUIS,

TELEPHON Application fiia July 12, 1897,

Tc aZZ whom, it may concern: Be it known that 1, WILLIAM DEAN, a citizen of the United States, residing at St. Louis, in the State of Missouri, have invented acertain new and usefulImprovement inTelephone Systems, (Case No. 23,) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to telephone-exchange apparatus adapted particularly for use in connection with party telephone-lines.

' The principal-feature of my invention relates to switchingmechanism under the control of the operator for including the callinggenerator in circuit with the signal of the selected subscriber.

Heretofore a plurality of push-keys equalv in number to the subscribers stations upon a party-line have been employed for signaling purposes. Such a system is illustrated in my application, Serial No. 622,264, filed February 6, 1897. In said system eight ringing-keys are employed in connection with each cord-circuit in addition to a mastenkey adapted to connect said keys with the cordcircuit. Each key upon being depressed is adapted to include current of a particular character to which the calling apparatus at the station corresponding tosaid key is responsive.

In party-line systems as equipped heretofore the operator and calling subscriber are both occasioned annoyance and delay if for any reason the called subscriber has to be signaled again, as upon the failure of said subscriber to respond to the first signal, since the operator after having made the connection and signaled the called subscriber im- TELEPHONE COMPANY OF MISSOURI, OF

SPECIFICATION forming part of Letters Patent No. 593,372, dated November 9,

' subscriber PATENT OFFICE.

MISSOURI, ASSIGNOR TO THE BELT.

SAME PLACE.

E SYSTEM.

Serialllo. 644,239. on model.)

telephone-line through a signal-bell at one of the subscribers stationsthere'of, a masterkey being preferably employed to connect the plugs with'the source. of calling-current. \Vith, such a system the operator after knowing the subscriber of a party telephone-line with whom communication is desired inserts one of i the plurality of connecting plugs which is adapted to include signaling-current to which the bell at the called-subscribers station will respond and then'depresses the master-key to connect the calling-generator in circuit with the plug. If, now, for any reason the calling subscriber should wish to have the called subscriber resignaled, the operator merely depresses the single key-- the master-key. 7 There are other features of my invent-ion which will be set forth hereinafter.

I .will explain ,my invention in with the accompanying drawings, in which- Figure 1 represents two metallic telephonelines connected with the central oflice, one of which is a party-line, and switching apparatus constructed in accordance with my invention. Fig. 2 illustrates a multiple-switchboard exchange with metallic-circuit telephone-lines connected therewith,one of which is a party-line, and a modified form of my improved switching apparatusat the central office.

Like letters and numerals refer to like parts in both of the views. Referring now more-particularly to Fig. 1, Ais connected with the central office by a single metallic-circuit line whose limbs 1 and 2 are connected with the short and long line springs c't'a of spring-jack a at the exchange. Subscribers B and B are connected with the-party-line metallic cirmediately forgets the particular key that she has depressed and the particular subscriber of the party-line that has been called, and in order to signal the called subscriber again this information has to be refurnished to the operator.

The principal feature of my invention consists in providing a plurality of connectingcuit whose limbs the short and long spring-jack b at the exchange. substations is provided with telephone-hook 0, receiver 0*, and call-bell A wellknown type shown at the exchange,

line springs bf 12 of the Each of the an automatic transmitter 0 of line-indicator is plugs .each connected or adapted to .be connected in the cord-circuit and each adapted to direct signaling-current over the party a well-known manner upon the removal of the receiver from any switch-hook at the sub scribers stations, which serves to complete 3 and 4 are connected with which is operated in connection .and connecting-'plugs c andf.

of plngf,

.nectcd, respectively,

the bridge-conductor 5, provided at each stati'on between-the limbs, of the corresponding telephone-line.

The telephone-switclrhooks at stations 13 and B are connected, respectively, with the limbs 4 and 3 of the party telephone-line, the

grounded bells at said stations" being conwith said limbs when. the receivers are supported by At the central office I have illustrated a cord;circuit comprising an answering-plug d The tlps of the answering-plug and connecting-plug f are connected by strand 6. The sleeves of said plugs are connected by the strand 7, tip of connecting-plug'e, and the cross-conductor 8. The tip of answering-plugdis connected with the sleeve of plug 2 by the strand 6, tip and the cross-conductor 9. Thus the tips and sleeves of" plugs d and fare re,- spectively connected, While the tip and sleeve of the answering-plug are connected, respectively, with the sleeve and tip of the connecting-plugs.- In a bridge between the strands 6 and 7 I haveincluded a retardation-coil g and battery 9. Between said bridge and the answering-plug I have. shown telephone-line,

have included a second current following conductor a clearing-out indicator 9 in the strand 6 responsive to the switching apparatus at the calling-subscribers station. Between said bridge conductor and r-connectin g plugs I clearing-out indicator 9 in strand 6 responsive to the switching apparatus at the called-subscribers station. Akey his includeddn the strand 7. The key is provided with a contact portion h, insulated therefrom and connected with the callinggenerator The operator is provided with a. listening-key It in a bridge be tween the cordstrands. Upon the depression of the key It the generator is connected with'th'e branch 10, extending from the strand 7 between the normal contact-anvil of the key h and the connecting-plugs. Upon the operationcf the key or tor'is thus connected with the tip of plug, e and sleeve of plug f.

Subscriber A, desiringcom'm unication with subscriber B, signals the operator, who after having inserted the answering-plug in the call: ing-subscribers spring -jack and depressed her listening-key togascertain the connection desired inserts the connecting-plug.in this instance plug finto the spring-jack oi the party-,lineand depressesthe ringing key or switch. h, whereby the calling-generator 2" is included in circuit with the signal-bell at the called station, the path taken by the calling 10, a portion of conductor 7, tip of plug e, cross-condu-ctorS, sleeve of plug f, line-spring b limb 40f the the portion of the bridge-condoctor 5 connecting the switch-hook with the limb lfof the party-line, the-switch-hook, and the grounded bell. The signaling-current can follow no other path, since the strand 7 is broken.

their'hooks,

l and grounded call-bell switch Zgthe generaspring-jacks are connected If the calling subscriber should desire communication with subscriber B of the PM, line, the operator inserts the connecting-plug 79 e into the spring-jack of said line, whereby upon the'depress'ion of; the ringing-key current from the calling-generator is directed, over conductor 10, a portion of conductor 7,1 tipoi' the connecting-pluge, limb 3 of the-" telephone-line, a .portion of the bridge-con: ductor 5 at station E, the telephone-switcly- J at said station. The current from generator path, since the strand 7 mal position, V

tion when said plug is idle. If the calling subscriber should desire to 851 have the called subscriber resignaled for example, in case the called subscriber 1 should fail to respond to the first signal-o: j

if the calling subscriberafterhaving finished one conversation should immediately desire to speak again to the called subscriber, he" t. vibrates his switch-"hook to rapidly operate his clearing-out signal 9 which indicates to the operator that it is desired tohave the. called subscriber resignaled. In systems heretofore in use where the; called subscriber was connected with a partyline it was necessary thatthe operator be again informed of the particular subscriber. 'of the party-line whoxwas to be resignalod. .In the present system the operator merely depresses the ringing-key upon the rapid op eration of the calling-subscribers clearingout signal, the proper connecting-plug being inserted to direct calling-current to the called! su-bscribers signal-bell.

Referring to Fig; 2, I have illustrated a multipleswitchboard system employing n cord -connecting apparatus. embodying my invention. the substations are similar to thoseremployed.

in the system shown in Fig. 1, the bells s 1;

ing; however, preferably of high resistance. Thecirouits are somewhat modified, the bells being included in ground branches perm'anently connected with the bridge-conductors ,5,'while condensers l are included in the? bridge-conductors, whereby battery-current from the centralized batterym is directed through the transmitters; no

The line-signals shown form no part of my l present invention, their operation being well I I understood by those skilled in the art.

' The spring-jacks 1* and 1 are disposed at one board, while the spring-jacks 2 and 2 are disposed at another board. Jacks 1 and 2 are provided with -1netallic-thimhles a a, while jacks 1 and 2 are provided with me-' tallic thimbles b 123,. these thimbles being connected. in multiple and grounded. The 15 in multiple with r their respectivetelephone-lines. Cord strand 1 6 contains repeating-coils mf m while cord strand '7 includes repeating-coils 'm m. The

can follow no other I is broken and sincoj so: the sleeve of the remaining connectin f, connected withlthe tip of plug e in' its nob.

has no other electrical connec- 7 The vinstruments employed at. IIO

battery m is connected at one terminal between the coils m m and at the other termi'-' nal between the coils m m. This arrangement is well-known to those skilled in the art. A third strand 11 connects the third contact portions n of the plugs, which engage the metallic thimbles whenthe plugs are inserted in the jacks. Clearing-out indicators 9 g are included in this strand.

I do not deem it necessary to describe the operation of the clearing-out annunciators, as they form no part of my present invention.

The battery 0 is included in the ground branch from strand 11.

I preferably operate the ringing-key h antomatically by means of an electromagnetic circuit-controlling device,.such as'is shown and described in my application, Serial No. 607,126, filed September 28, 1896. Forthis purpose I include an electromagnet k in circuit with the conductor 11, the armature of the magnet supporting the 'ringing key or switch h, this magnet being energized upon the insertion of one of the connecting-plugs into a spring-jack. When the plug is inserted, current is directed from the battery 0 through the said magnet, contact portion '22, of the inserted connecting-plug, through the relay 1?, constituting a portion of the line-indicating apparatus, to ground. In this instance-the key his composed of two strips h h of spring metal insulated from each other. Strip 72, is connected with tip of plug 1, While strip 7% is connectedwvith sleeve of plug e. Upon the attraction of the armature of the magnet h the key h is limited in'its down ward movement by the post g, the strips h if being thereby brought into engagement with the generator-contacts 7L hirespectively, whereby the generator or sourceof callingcurrent i is included in circuit with the inserted connecting-plug and the correspondin g limb of the telephone-line engaging'the terminal of said plug connected with the generator, whereby the bell at the selected station is operated. When the ringing-switchi thus engaged by the post q, the strips k #are.

freed from all contacts except the generatorcontacts to open the cord-circuit between the connecting-plugs andbattery m, whereby current from the generator is prevented from passing over the remainder of the cord-c ircuit and by wayof battery 'm to the bell at the remaining and uncalled station of the party-line or to prevent the generator from being short-circuited by ground m The called subscriber in response to the signal removes his telephone from its hook, whereby the current from the generator finds a return path to ground m at the central office, the new path for the generator-current offering less resistance. The obstructing portion 'qis mounted upon the armature of a magnet 1", traversed by the calling-current, and when said magnet is operated by reason of the increased current passing t rough the same upon the removal of thecalled-subscriberstelephone from its hook said .obstruc- 1 tion q is removed from the I path of the key, permitting the springs h h to come in contact with the contact-anvils beneath the same to complete the continuity of the cord-circuit and to disengage the said springs from the generator-contacts to remove the generator from line. The tip of plug e is grounded at m. A test-conductor12 normally connects the tips of the plugs, said conductor terminating in the normal contact of spring h", connected with tip of plug f. Both tips of the connecting-plugs are thus grounded,

, the operator being thereby enabled to use either-one for the purpose of testing. If the line called for should be in use at another board, this fact is evidenced upon an application of either connecting-plug to the thimble of the jack at the board where the call is made. In testing the battery cat the board where the line .may be in use finds a path through said thimble, the tip of the applied connecting-plug, strand 6, repeating-coil m to ground m the test being manifested by a click in the operators telephone.

The terms answering-plug and connecting-plug are well recognized in the art of telephony as tions of the cord-connecting apparatus. The answering-plug is that plug'used by the operator to establish connection betweenthe calling-subscribers apparatus and through the medium of which the operator connects her telephone in circuitwith the calling-subscribers telephone,

whereby the connection desired by the sub-- scriber may be ascertained. The connecting-.

plug is the plug by which the called-subscribers line is included in circuit with the cordcircuit and the calling-subscribers line and through the medium whereof theringing-current is included in circuit with the called-subs'cribers signal-bell. In the claims I use the terms connecting-plug, and answeringplug in the sense as pointed out above. In the claims I speak of grounded branches at the subscribers stations and a grounded source of calling-current in the sense that circuit is completed through them by a grounded return oradditional conductor independent of the telephonic circuit.

Inthe claims I use the term signal-bell in the sense of any signal-receiving 'appara tus located at the subscribers stations.

It is obvious that my'invention may be ap-' plied to other systems than those herein shown and that modifications may be'readily made without departing from the spirit of my invention. I do not therefore desire to be limited to the precise system of circuits and apparatus herein shown and described; but, g Having thus described my invention, I claim as new, and desire to securebyLetters Patent, together with such modifications as may be made by those skilled in the art, the following: I

descriptive of distinct porline and the operators 1. In a telephone exchange system the I telephone-line extending from the exchange,

combination with a telephone-line and a party telephone-line extending from the exchange,- of a cord-circuit for forming a continuation of the first-aforesaid telephone-line, a plureality of connecting plugs, each severally adapted} to connect the cord-circuit and the first-aforesaid telephone-line with the party telephone-line, signal-bells at the subscribers stations of the party-line, and a' source of signaling-current connected or adapted to be connected with each connecting-plug, each connecting-plug corresponding to a subscribers station of the party-line and adapted to include signaling-current in circnit with' "the signal-bell thereat, the bells at the re- Y maining station or stations being irresponrality of connectingsive tothe signaling-current thus included in circuit with the bell at the selected station, substantially as described.

2.7 Ina telephone-exchange system, the combination'with a telephone-line and a party telephone-line extending from the exchange, of a cord-circuit for forming a continuation of the first-aforesaid telephone-line, a pluplugs, each severally adapted to connect the cord-circuit and the first aforesaid telephone-line with the party telephone-line, sig'nal-bells'at the subscrib-. e'r's stations of the party-line, a source of signaling-current connected or adapted to be connected with each connecting-plug, each connecting-plug'corresponding to asubscribers station of the party-line and adapted to include signaling-current in-circuit with the v signal-bell thereat, the bells at theremainin g station'or stations being irresponsive to the. signalingcurrent 'thus included. in circuit with the 'bell at the selected station, and switching mechanism for connecting the source ,of-calling-current with or disconnecting it from the connecting-plugs, substantially'as described. I

3.' I n atelephone exchange system, the

combinationwit'h a metallic party telephone line circuit connected at the centraloflice with a line or spring jack switch having two substations connected therewith, each'limb of the line' haying'asignal-bell connected in circuit therewith at each subscribers station,

a source of calling-current, a cord-circuit for connecting subscribers for conversation hav- ,ing two strands, and connecting plugs form ing a part thereof, each connecting-plug be-' ing provided with twodissimilar contact portiens as a tip anda sleeve and adapted for insertion in said spring-jack switch, the tip and sleeve of one plug bein'gconnected respectively with v the sleeve and-tip gift the other plug, eachof said plugs corresponding to one substation and adapted to-direct current in circuit with the signal-bell thereat,

said plugs being connected or adapted to be 4'. In a telephone-exchange system, the-1 combination witha telephone lineand a party of a cord-circuit, an an plurality of connecting-plugs connected therewith, the answerin g-plugbein g provided swering-plug and afor connecting the cord-circuit with the firstaforesaid telephone-line, connecting-plugs-"is the party-line with the cord-circuit and the while each of said provided for connecting other telephone-line, signal-bells atthe subscribers stations of the party-line, and a adapted to be connected with each connectin'g-plug, each connecting-plug corresponding to a subscribers station of the party-line with a line or spring jack and having-two circuit therewith at each subscribers station,

ing a part thereof, sponding to -one substation and adapted. to

thereat, said controlled thereby andv adapted to connect cuit-controlling device of said key whereby the key is limited in its magnet "1 controlled by the apparatus at the said portion key whereby the source of calling current is 6. In a multiple-switchboard system, the

combination with two or more switchboards at the central ofiice, of a telephone-line, and

line iacks at all of said switchboar'ds, a cordcircuit for forming-a continuation of the firstto connect the telephone-line and cord-circuit the subscribers stations of the party-line, '8

adapted v ing-plug, each connecting-pl ugcorresponding cuit with the signal-bell 'th'creat, the

source of signaling-current connected :or

5. In a telephone-exchange systempthe line circuit connected at the central ofllca' a source of calling-current, a eord-circuit'lor. connecting subscribers for conversation hay- A ing two strands, twoconnecting-plugs formeach of said plugs corre'e direct current in circuit with the signal-boll: plugs being connected or adapted to be connected with the aforesaid source of calling current, an electromagnetic circuit-j controlling device having a ringing-key h called subscribers station adapted to remove g from the path of the ringing-.

aforesaidtelephone-line, a plurality of connecting-plugs, each severally being adapted.

and adapted to include signaling-currentini circuit with the signal-bell thercat, the bells" 5 cluded in circuit with'the bell at the selectedsubstations connected therewith, each. limb: of the line having a signal-bell connected in 15 the source of calling-current with said plugs, meansforclosing circuit through said cirwhereby said key is operated, aportion q interposed in the path V "1 IO motion and brought into contact with'a terminal of the source of calling-current, and a removed from line, substantially-as described.

a party telephone-line, each connected with with the party telephone-line, signal-bells at source of signaling-current connected or I to be connected with eachvconnect jsq to a subscribers station'of the partylineand V adapted to include signaling-current inch.

the remaining station or stations being irresponsivc to the signaling-current thus included in circuit with the bell at the selected atT-g-n, a test portion as a thirnble associated w ith each line-jack connected withthe party telephone-line, a portion of a test-circuit con= nected or adapted'to be connected with each of said test portions, and test portions upon each ot said connecting-plugs, the remaining portion of said test-circuit being connected with one of the test portions of a connect-ingplug, the test portions of the connecting-plugs being or adapted to be electrically connected, substantially as described.

7. In a telephone-exchange system, the combination with a telephone-line and a party telephone-line extending in two limbs from the exchange to two substations, of agrounded branch from each limb of the party-line, one branch being located at each. substation, signal-bells included in the grounded branches, at cord-circuit for forming a continuation of the first-aforesaid telephone-line,

ed to connect the cord-circuit and the firstaforesaid telephone-line with the party telephone-line, and a grounded source of callingcurrent connected or adapted to be connected plug being adapted to direct the calling-current over one limb of the party-line to operate the signal-bell at one station, while the other connecting-plug is adapted to direct calling-current over the other limb of the party-line to operate the signal-bell at the station may be selected and alone operated,

substantially as described.

In Witness whereof I hereunto subscribe my name this-8th day of July, A. D.,.1897.

' ILLIAM W. DEAN.

Witnesses:

W. E. HARKNESS, FRED R. Mo'r'r.

two connecting-plugs, each, severally, adapt-- with each connecting-plug, one connecting-- other station, whereby the signal-bell at either 1 

